Aortic Stenosis Flashcards
(12 cards)
What are the “classical” symptoms of aortic stenosis
Syncope / Presyncope
Dyspnoea
Angina
Sudden Death
N.B. The development of symptoms indicates that decompensation is occurring with myocardial ischaemia and heart failure
Give the echocardiographic values for severe AS for:
Peak Aortic Flow Velocity (m/s)
Peak and Mean Transaortic Pressure gradient (mmHg)
Valve area and valve area indexed to body surface area (cm2 and cm/m2)
Peak aortic Flow Velocity >4m/s
Peak Transaortic Pressure Gradient > 65mmHg
Mean Transaortic Pressure Gradient > 40mmHg
Valve Area <1.0cm2
Valve Area indexed to Body Surface Area <0.6cm/m2
It is recognised that aortic stenosis can occur in the absence of elevated flow velocity or mean pressure gradient and hence it is the valve area that is the unifying diagnostic criterion.
As a failing left ventricle will not be able to generate a significant velocity which would lead to an underestimation in severity if only using velocity and pressure measurements.
Equally an overestimation of severity can occur if the cardiac output is insufficient to cause adequate valve opening if a relatively normal valve and hence resulting in the appearance of a small valve area aka pseudo stenosis
Give the echocardiographic values for moderate AS for:
Peak Aortic Flow Velocity (m/s)
Peak and Mean Transaortic Pressure gradient (mmHg)
Valve area and valve area indexed to body surface area (cm2 and cm/m2)
Peak aortic Flow Velocity 3-4m/s
Peak Transaortic Pressure Gradient 40-65mmHg
Mean Transaortic Pressure Gradient 25-40mmHg
Valve Area 1.0-1.5cm2
Valve Area indexed to Body Surface Area 0.6-0.85cm/m2
It is recognised that aortic stenosis can occur in the absence of elevated flow velocity or mean pressure gradient and hence it is the valve area that is the unifying diagnostic criterion.
As a failing left ventricle will not be able to generate a significant velocity which would lead to an underestimation in severity if only using velocity and pressure measurements.
Equally an overestimation of severity can occur if the cardiac output is insufficient to cause adequate valve opening if a relatively normal valve and hence resulting in the appearance of a small valve area aka pseudo stenosis
Give the echocardiographic values for mild AS for:
Peak Aortic Flow Velocity (m/s)
Peak and Mean Transaortic Pressure gradient (mmHg)
Valve area and valve area indexed to body surface area (cm2 and cm/m2)
Peak aortic Flow Velocity <3m/s
Peak Transaortic Pressure Gradient <40mmHg
Mean Transaortic Pressure Gradient <25mmHg
Valve Area >1.5cm2
Valve Area indexed to Body Surface Area >0.85cm/m2
It is recognised that aortic stenosis can occur in the absence of elevated flow velocity or mean pressure gradient and hence it is the valve area that is the unifying diagnostic criterion.
As a failing left ventricle will not be able to generate a significant velocity which would lead to an underestimation in severity if only using velocity and pressure measurements.
Equally an overestimation of severity can occur if the cardiac output is insufficient to cause adequate valve opening if a relatively normal valve and hence resulting in the appearance of a small valve area aka pseudo stenosis
Give the normal echocardiographic values for the aortic valve for:
Peak Aortic Flow Velocity (m/s)
Peak and Mean Transaortic Pressure gradient (mmHg)
Valve area (cm2)
Peak aortic Flow Velocity <2m/s
Peak Transaortic Pressure Gradient <10mmHg
Mean Transaortic Pressure Gradient <5mmHg
Valve Area 3-4cm2
It is recognised that aortic stenosis can occur in the absence of elevated flow velocity or mean pressure gradient and hence it is the valve area that is the unifying diagnostic criterion.
As a failing left ventricle will not be able to generate a significant velocity which would lead to an underestimation in severity if only using velocity and pressure measurements.
Equally an overestimation of severity can occur if the cardiac output is insufficient to cause adequate valve opening if a relatively normal valve and hence resulting in the appearance of a small valve area aka pseudo stenosis
List the factors that would favour Transcatheter Aortic Valve Implantation (TAVI) over a surgical aortic valve replacement
Patient Factors:
Increased Age
“Severe” Comorbidities
Surgical Factors:
Previous cardiac surgery
Previous Aortic Valve Replacement (due to increased risk associated with redo sternotomy)
Favorable vascular access
Heavily calcified aorta (as this can prevent safe aortic cross clamping)
Only aortic valve surgery required (I..e. other valves are normal as are the coronary arteries)
Chest wall deformity
NB with recent evidence from PARTNER 2 & 3 and SURTAVI Trials that have shown TAVI had no difference to open surgery in mortality and major morbidity in low and intermediate risk patients as well as having a lower risk of complication such as AF AKI and Haemorrhage it is being performed on increasingly younger patients with few co-morbidities
What is the absolute contraindication to Transcatheter Aortic Valve Implantation (TAVI)
Infective endocarditis
What are the relative contraindication to Transcatheter Aortic Valve Implantation (TAVI)
Patient co-morbidities:
Such that the procedure would not improve the patients quality of life or life expectancy
Anatomical factors:
Aortic annulus size
Distance between annulus and coronary ostia
What anaesthetic options are there for a patient presenting for a TAVI
General Anaesthesia
Local Anaesthesia with conscious sedation (achieved with target controlled propofol infusion or intermittent bolus regimens of fentanyl or midazolam)
Local Anaesthesia only, which is increasingly common with local anaesthesia being given only at the vascular access site
What are the haemodynamic goals when anaesthetising a patient undergoing a TAVI
Maintenance of Preload
Maintenance of Sinus Rhythm
Maintenance of Normal Heart Rate
Maintenance of Cardiac Contractility
Maintenance of afterload / blood pressure
What are the causes of haemodynamic instability in a patient undergoing a TAVI
Major haemorrhage due to an iatrogenic injury to the aortic root, annulus or intrathoracic blood vessels.
Arrhythmia due to damage to the AV node or bundle of HIS upon deployment of the valve
Cardiac Ischaemia due to occlusion of the ostia by the implant
Rapid ventricular pacing up to 200bpm,which is intentionally performed as part of the TAVI procedure to dramatically reduce cardiac output for up to 10 seconds, during valve deployment to prevent its migration.
What are the complications of TAVI insertion
Stroke
Abnormal Valve placement
Complications related to vascular access
